Statistical analysis was done using one-way ANOVA test and Kruskal-Wallis test (α=.05).
The group repaired with bis-acryl composite without additional surface treatment showed the highest mean shear bond strength. It was significantly higher than all four groups repaired with methylmethacrylate (&lt;.05). Additional surface treatments, neither mechanical nor chemical, increased the shear bond strength within methylmethacrylate groups and bis-acryl composite groups (&gt;.05). Failure mode analysis showed that cohesive failure was most frequent in both methylmethacrylate and bis-acryl composite groups.
Our results suggest that when repairing 3D printed provisional restoration with conventional provisional resin, repair with bis-acryl composite without additional surface treatment is recommended.
Our results suggest that when repairing 3D printed provisional restoration with conventional provisional resin, repair with bis-acryl composite without additional surface treatment is recommended.The stress distribution and microgap formation on an implant abutment structure was evaluated to determine the relationship between the direction of the load and the stress value.
Two types of three-dimensional models for the mandibular first molar were designed bone-level implant and tissue-level implant. Each group consisted of an implant, surrounding bone, abutment, screw, and crown. https://www.selleckchem.com/products/c-75.html Static finite element analysis was simulated through 200 N of occlusal load and preload at five different load directions 0, 15, 30, 45, and 60°. The von Mises stress of the abutment and implant was evaluated. Microgap formation on the implant-abutment interface was also analyzed.
The stress values in the implant were as follows 525, 322, 561, 778, and 1150 MPa in a bone level implant, and 254, 182, 259, 364, and 436 MPa in a tissue level implant at a load direction of 0, 15, 30, 45, and 60°, respectively. For microgap formation between the implant and abutment interface, three to seven-micron gaps were observed in the bone level implant under a load at 45 and 60°. In contrast, a three-micron gap was observed in the tissue level implant under a load at only 60°.
The mean stress of bone-level implant showed 2.2 times higher than that of tissue-level implant. When considering the loading point of occlusal surface and the direction of load, higher stress was noted when the vector was from the center of rotation in the implant prostheses.
The mean stress of bone-level implant showed 2.2 times higher than that of tissue-level implant. When considering the loading point of occlusal surface and the direction of load, higher stress was noted when the vector was from the center of rotation in the implant prostheses.The purpose of this study was to evaluate the occurrence of displacement while tightening the screw of scan bodies, which were compared according to the material type.
Three types of scan bodies whose base regions were made up of polyether ether ketone (PEEK) material [Straumann Group, Dentium Group, and Myfit (PEEK) Group] and another scan body whose base region was made up of titanium material [Myfit (Metal) Group] were used (15 per group). The reference model was fabricated by aligning the scan body library on the central axis of the implant, and moving this position by the resin model. The screws of the scan bodies were tightened to the implant fixture with torques of 5 Ncm, 10 Ncm, and a hand tightening torque. After the application of the torque, the scan bodies were scanned using a laboratory scanner. To evaluate the vertical, horizontal, and 3-dimensional (3D) displacements, a 3D inspection software program was used. To examine the difference among groups, one-way analysis of variance and Tukey's HSD post hoc test were used (α=.05).
There were significant differences in 3D, vertical, and horizontal displacements among the different types of scan bodies (&lt;.001). There was a significantly lower displacement in the Straumann group than in the Myfit (PEEK) and Dentium groups (&lt;.05).
The horizontal displacement in all groups was less than 10 ?m. With the hand tightening torque, a high vertical displacement of over 100 ?m occurred in PEEK scan bodies (Myfit and Dentium). Therefore, it is recommended to apply a tightening torque of 5 Ncm instead of a hand tightening torque.
The horizontal displacement in all groups was less than 10 ?m. With the hand tightening torque, a high vertical displacement of over 100 ?m occurred in PEEK scan bodies (Myfit and Dentium). Therefore, it is recommended to apply a tightening torque of 5 Ncm instead of a hand tightening torque.The aim of this study was to evaluate the accuracy of six recently introduced intraoral scanners (IOSs) for single crown preparations isolated from the complete arch, and to determine the effect of scanning sequence on accuracy.
A complete arch with right and left canine preparations for single crowns was used as a study model. The reference dataset was obtained by scanning the complete arch using a highly accurate industrial scanner (ATOS Core 80, GOM GmbH). Six different IOSs (Trios, iTero, Planmeca Emerald, Cerec Omnicam, Primescan, and Virtuo Vivo) were used to scan the model ten times each. The scans performed with each IOS were divided into two groups, based on whether the scanning sequence started from the right or left quadrant (n=5). The accuracy of digital impression was evaluated using three-dimensional analyzing software (Geomagic Studio 12, 3D Systems). The Kruskal Wallis and Mann-Whitney U statistical tests for trueness analysis and the One-way ANOVA test for precision analysis were performed (α=.05).
The trueness and precision values were the lowest with the Primescan (25 and 10 ?m), followed by Trios (40.5 and 11 ?m), Omnicam (41.5 ?m and 18 ?m), Virtuo Vivo (52 and 37 ?m), iTero (70 and 12 ?m) and Emerald (73.5 and 60 ?m). Regarding trueness, iTero showed more deviation when scanning started from the right (=.009).
The accuracy of digital impressions varied depending on the IOS and scanning sequence used. Primescan had the highest accuracy, while Emerald showed the most deviation in accuracy for single crown preparations.
The accuracy of digital impressions varied depending on the IOS and scanning sequence used. Primescan had the highest accuracy, while Emerald showed the most deviation in accuracy for single crown preparations.